In order to increase the integration time for a scanned two-dimensional (2-D) imaging sensor, the technique of back-scanning is often used to provide step/stare coverage. FIGS. 1A-1C illustrate this concept. In a sensor system, an afocal telescope 110 is configured to receive incoming electromagnetic radiation 120 and direct the radiation via imaging optics 130 to an imaging sensor, which is frequently a focal plane array (FPA) 140. Movement of the sensor system causes blurring of the image obtained by the FPA 140. Back-scanning with a mirror 150 behind the afocal telescope 110 provides an agile method to increase the integration time for the FPA 140 by at least partially compensating for movement of the sensor system. Specifically, as the sensor system moves, the back-scan mirror 150 attempts to hold the image stable on the FPA 140 during the integration time. This is illustrated in FIG. 1C, which shows the FPA's field of view 160 moving within the angular field of view 170 of the afocal telescope 110 as a result of the back-scanned motion 180 during the exposure. Thus, the larger sensor system may be scanned at the nominal rate while the smaller back-scan mirror 150 provides the fast motions to implement the step/stare function.